BLACK+DECKER CM2040 stalls on grass

yardwoman

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I have a BLACK+DECKER CM2040 40V Lithium 3-in-1 Cordless Mower, 20". About a month ago, the mower started stalling when on the lawn. If I move it to the sidewalk it will run. On the grass it will sputter and die. I found that if I tilted the mower back toward me, I could keep it running for a while. I raised the height of the mower, that did not help. I thought may be blade was dull. I had the blade sharpened. Still no go. The batteries are charged. I do not want to buy another mower. Your advice is appreciated. Thank you.
 

Mark Widmer

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It's possible the battery is damaged or "not quite dead" -- since it will run the mower on pavement, but then adding the load of cutting grass to the motor could make the battery voltage drop below the level that some circuitry decides is too low, and then shuts off the motor at that point.

Is the battery very old? You might try replacing it, and see how things go.

Mark
 

spikester

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I'm having the same problem. At first, I raised the level a bit and it worked for a while. Now, as soon as I put a load on it, it dies. But it runs great when it just sits on the cement walkway.
 

JimShane525

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And I have the same problem as well. I have several batteries which I keep charged, so it's not an old battery. I have a small city lot, so I can mow the lawn with this annoyance. But, I have to restart the engine after every sweep. (sometimes several times within it).

My brother thought the issue must be some kind of fuse which is failing, and overheats easily. And he thought that the fuse must be somewhere on the cord from the start button to the engine. But, I can't see where any such thing might exist. I think the issue began a year and a half ago - i ran over some sticks that must have overloaded the blade. I've cleaned any dried grass and debris from around the blade several times - so it's not that.
 

BobDoug

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I am now having a similar problem with myCLMA4820L2. I stumbled onto a product description that noted a Autosense feature that adjusts the power depending on the load, to conserve battery life when the mowing is light. By a process of elimination I think this is my problem. However, I have no idea how to get this fixed. suggestions?
 

BobDoug

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After a process of elimination, I became convinced that the problem was with the "battery controller" that is in this mower, ostensibly to extend the life of the battery by adjusting the power delivered to the motor depending on the load on the blade. I suspect this is essentially an auto throttle, controlling the speed of the motor. I ordered the part with the help of a Black and Decker rep, since version of the mower I bought from Menards did not come with any useful documentation. Took 10 days to arrive! Switching it out took about 30 minutes. Lot's of wires, so a bit fussy but not difficult. This seems to have fixed the problem, but not completely. Now the mower runs for awhile, then dies. But, now, it will start right back up. I wish I knew why, but it is better than buying a new mower.

I just wish manufacturers would adopt KISS...Keep It Simple Stupid. This complication is unnecessary, IMHO.
 
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